It is generally known within the opto-electronic field to exactly align optical fibres with a high grade of accuracy by receiving the fibres in etched out grooves, so called V-grooves, in silicon substrates.
However, when mounting the optical fibres in such grooves, it can be difficult to make the optical fibres stay in place in the respective groove during all of the mounting operation.
When gluing the optical fibres to the grooves, it has, more-over, been observed that the optical fibres will rise some-what in the grooves due to the thickness of the glue layer, and, consequently, the position of the respective optical fibre in the vertical direction as well as the lateral direction on the substrate will be indefinite.